The invention relates to the treatment of bone conditions in humans and other animals.
Several companies offer mechanical bone cement injection devices. These devices are similar to a household caulking gun. Typically, the injection device has a pistol-shaped body, which supports a cartridge containing bone cement. The cement is typically in two-parts and must be mixed in a mixer and transferred into the cartridge for injection.
Just after mixing, and prior to curing, the cement is in a flowing, viscous liquid state, similar to a syrup or watery pancake batter in consistency. The injection device has a ram, which is actuated by a manually movable trigger or screwing mechanism for pushing the viscous bone cement out the front of the cartridge through a suitable nozzle and into the interior of a bone targeted for treatment.
Once injected into the targeted bone, the cement undergoes a curing cycle of perhaps 6 to 8 minutes. While curing, the cement passes from a viscous liquid to a putty-like consistency and finally to a hard rigid block.
The invention provides, in its various aspects, greater control over the placement of cement and other flowable liquids into bone.
One aspect of the invention provides an assembly for injecting flowable material into bone. The assembly comprises a tubular body including an interior bore to carry a material flow. The tubular body has a longitudinal axis and includes a dispensing end. An opening in the dispensing end communicates with the bore to dispense the material flow. A plunger is located at least partially within the tubular body. The plunger is adapted to be displaced along the longitudinal axis of the tubular body. The assembly includes an advancement mechanism that is attached to the plunger. The advancement mechanism displaces the plunger a first longitudinal displacement in response to a first delivery impulse, and a second longitudinal displacement in response to a second delivery impulse.
Features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended claims.